Benzimidamides compounds comprising an oxaborinin ring

ABSTRACT

The invention relates to 4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide derivatives and their use in treating diseases and conditions of the skin (for example, Netherton syndrome, rosacea, atopic dermatitis, psoriasis and itch) caused by abnormally high levels of protease activity (particularly of serine proteases such as kallikreins). In addition, the invention relates to compositions containing the derivatives and processes for their preparation.

FIELD OF INVENTION

The invention relates to4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamidederivatives and their use in treating diseases and conditions of theskin (for example, Netherton syndrome, rosacea, atopic dermatitis,psoriasis and itch) caused by abnormally high levels of proteaseactivity (particularly of serine proteases such as kallikreins). Inaddition, the invention relates to compositions containing thederivatives and processes for their preparation.

BACKGROUND OF THE INVENTION

Netherton syndrome is a genetic skin disease characterised by abnormaldesquamation and chronic skin inflammation. The loss of skin barrierfunction leads to severe dehydration and a high susceptibility toinfection. There is a high rate of postnatal mortality, and a generalfailure to thrive early in life. Patients suffer from a persistentpruritus (itching). Erythroderma is common and ichthyosis oftendevelops. All patients become atopic, manifesting both in the skin andas food allergies.

Netherton syndrome is caused by mutations in the SPINK-5 gene, and isinherited in an autosomal recessive manner. There are over 40 knownmutations, but all result in partial or complete loss of expression ofthe gene product, lympho-epithelial Kazal-type-related inhibitor (LEKTI)in the skin (Chavanas et al, Nature genetics (2000), 25(2), 141-2).

LEKTI is a serine protease inhibitor that is expressed in the mostdifferentiated layer of the epidermis, along with serine proteases suchas kallikreins 5, 7 and 14 (KLK-5, -7 and -14). Under normal conditions,LEKTI inhibits protease activity in the lower levels of epidermis, butthis inhibition is lost in the more acidic outer layers of the stratumcorneum, allowing cleavage of the corneodesmosomes and loss of theoutermost layer (desquamation). The absence of LEKTI increases proteaseactivity in the stratum corneum which results in inappropriate cleavageof desmosomal proteins and loss of the entire outer skin layer.

Abnormal protease activity within the epidermis also activates PAR-2 andtriggers an inflammatory reaction characterised by increased Th-2 typecytokines such as TSLP. This leads to the observed erythroderma, and theprofound pruritus that is characteristic of the disease. The biasing ofthe immune system towards a TH2 response so early in life also explainsthe high prevalence of atopy in these patients.

Inhibition of KLK-5 activity in the outer layers of the skin willcounteract the partial or complete absence of LEKTI, which drivesNetherton Syndrome. This will restore skin barrier function by reducingabnormal desquamation and decrease erythroderma and itching bypreventing activation of PAR-2 receptors, decreasing the subsequentinflammatory drive.

Rosacea is an inflammatory skin disease that is estimated to affect 3%of the US population over 30 years of age and is characterized byerythema, papulopustules and telangiectasia. Increased protease activityin the skin has been reported in rosacea (Yamasaki K, et al. Nat. Med.(2007) 13: 975-80). A number of works confirm the pathophysiologicalrole of an increased expression of KLK-5 in rosacea (Two A, et al., JClin Aesthet Dermatol (2014) 7(1): 20-25). Also, it has been shown thatan active ingredient for treating rosacea, such as azelaic acid, has atherapeutic action of inhibiting KLK-5 (Coda A. et al., J Am AcadDermatol (2013) 69(4): 570-577. These data show the usefulness ofinhibitors of the kallikrein protease pathway, and especially ofinhibitors of KLK-5 for treating rosacea.

Atopic dermatitis (AD) is a chronic inflammatory skin diseasecharacterised by eczema, pruritus and cutaneous hyperactivity toenvironmental factors. Clinically unaffected skin in AD manifestsimpaired skin barrier function favouring microbe and allergenpenetration. AD most often starts in childhood before the age of 5 yearsand approximately 25% of children continue to suffer with the conditionthrough adulthood. Polymorphisms in SPINK-5 have been associated withatopic dermatitis (Walley et al, Nature Genetics 29 (2001)) andaccordingly inhibition of the KLK pathway may be effective at treatingAD.

Psoriasis is a chronic inflammatory skin disease characterised bydisordered keratinocyte proliferation and differentiation, this causespatches of red, flaky, crusty skin covered with silvery scales which maybe sore or itchy. The extent of the patches may vary in severity fromsmall and localized to complete body coverage. In psoriatic lesions,T-cell and dendritic cell activation leads abnormal protease activity(Komatsu, N. et al, British Journal of Dermatology (2007) 156(5):875-883) and accordingly inhibition of the KLK pathway may be effectivein treating psoriasis.

In light of the role serine protease enzymes such as KLK-5 play in thecleavage of desmosomal proteins, it is desirable to prepare compoundsthat inhibit KLK-5 activity, which compounds may be useful in thetreatment of diseases and syndromes mediated by the KLK-5 pathway.

BRIEF SUMMARY OF THE INVENTION

According to a first aspect, the invention provides a compound offormula (I) or a pharmaceutically acceptable salt thereof,

wherein R¹, R² and R³ are defined herein.

Further aspects of the invention include:

-   -   i) methods of treating diseases and conditions mediated by the        KLK-5 pathway using a compound of formula (I) or a        pharmaceutically acceptable salt thereof; exemplary diseases and        conditions include, but are not limited to Netherton syndrome,        rosacea, atopic dermatitis, psoriasis and itch.    -   ii) pharmaceutical compositions comprising a) a compound of        formula (I) or a pharmaceutically acceptable salt thereof and b)        a pharmaceutically acceptable carrier or excipient; and    -   iii) uses of a compound of formula (I) or a pharmaceutically        acceptable salt thereof for treating diseases and conditions        mediated by the KLK-5 pathway.

DETAILED DESCRIPTION OF THE INVENTION

According to a first aspect, the invention provides a compound offormula (I) or a pharmaceutically acceptable salt thereof,

-   -   wherein    -   R¹ is H, R² is CF₃ and R³ is 3-pyridylmethoxy, 3-chlorobenzyloxy        or H;    -   R¹ is Cl, R² is F and R³ is 3-pyridylmethoxy; or    -   R¹ is H, R² is H and R³ is 3-pyridylmethoxy.

In an embodiment, the compound of formula (I) is selected from the groupconsisting of:

-   4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide    (Compound 1);-   2-((3-chlorobenzyl)oxy)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide    (Compound 5);-   4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide    (Compound 6);-   4-(6-chloro-7-fluoro-1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide    (Compound 7); and-   4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide    (Compound 8);    or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is2-((3-chlorobenzyl)oxy)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is4-(6-chloro-7-fluoro-1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.

The compounds of formula (I) as defined in the first aspect contain abasic centre and may form non-toxic acid addition salts formed withinorganic acids such as hydrochloric, hydrobromic, hydroiodic, sulfuricand phosphoric acid, with carboxylic acids or with organo-sulfonicacids. Examples include 4-acetamidobenzoate, acetate, adipate, alginate,ascorbate, aspartate, benzenesulfonate (besylate), benzoate, bisulfate,bitartrate, butyrate, calcium edetate, camphorate, camphorsulfonate(camsylate), caprate (decanoate), caproate (hexanoate), caprylate(octanoate), cinnamate, citrate, cyclamate, digluconate,2,5-dihydroxybenzoate, disuccinate, dodecylsulfate (estolate), edetate(ethylenediaminetetraacetate), estolate (lauryl sulfate),ethane-1,2-disulfonate (edisylate), ethanesulfonate (esylate), formate,fumarate, galactarate (mucate), gentisate (2,5-dihydroxybenzoate),glucoheptonate (gluceptate), gluconate, glucuronate, glutamate,glutarate, glycerophosphorate, glycolate, hexylresorcinate, hippurate,hydrabamine (N,N′-di(dehydroabietyl)-ethylenediamine), hydrobromide,hydrochloride, hydroiodide, hydroxynaphthoate, isobutyrate, lactate,lactobionate, laurate, malate, maleate, malonate, mandelate,methanesulfonate (mesylate), methylsulfate, mucate,naphthalene-1,5-disulfonate (napadisylate), naphthalene-2-sulfonate(napsylate), nicotinate, nitrate, oleate, palmitate,p-aminobenzenesulfonate, p-aminosalicylate, pamoate (embonate),pantothenate, pectinate, persulfate, phenylacetate,phenylethylbarbiturate, phosphate, polygalacturonate, propionate,p-toluenesulfonate (tosylate), pyroglutamate, pyruvate, salicylate,sebacate, stearate, subacetate, succinate, sulfamate, sulfate, tannate,tartrate, teoclate (8-chlorotheophyllinate), thiocyanate, triethiodide,undecanoate, undecylenate, and valerate. Pharmaceutically acceptablesalts include, amongst others, those described in Berge, J. Pharm. Sci.,1977, 66, 1-19, or those listed in P H Stahl and C G Wermuth, editors,Handbook of Pharmaceutical Salts; Properties, Selection and Use, SecondEdition Stahl/Wermuth: Wiley-VCH/VHCA, 2011 (seehttp://www.wiley.com/WileyCDA/WileyTitle/productCd-3906390519.html).

Salts may be prepared in situ during the final isolation andpurification of a compound of formula (I). Alternatively, salts may beprepared by methods known to the art, including treatment with aninorganic or organic acid.

It will be understood that if a compound of formula (I) contains two ormore basic moieties, the stoichiometry of salt formation may include 1,2 or more equivalents of acid. Such salts would contain 1, 2 or moreacid counterions, for example, a dihydrochloride salt.

Stoichiometric and non-stoichiometric forms of a pharmaceuticallyacceptable salt of a compound of formula (I) are included within thescope of the invention, including sub-stoichiometric salts, for examplewhere a counterion contains more than one acidic proton.

It will be appreciated by those skilled in the art that certainprotected derivatives of the compounds defined in the first aspect,which may be made prior to a final deprotection stage, may not possesspharmacological activity as such, but may, in certain instances, beadministered orally or parenterally and thereafter metabolised in thebody to form compounds defined in the first aspect which arepharmacologically active. Such derivatives may therefore be described as“prodrugs”. All protected derivatives and prodrugs of compounds definedin the first aspect are included within the scope of the invention.Examples of suitable pro-drugs for the compounds of the presentinvention are described in Drugs of Today, Volume 19, Number 9, 1983, pp499-538 and in Topics in Chemistry, Chapter 31, pp 306-316 and in“Design of Prodrugs” by H. Bundgaard, Elsevier, 1985, Chapter 1 (thedisclosures in which documents are incorporated herein by reference). Itwill further be appreciated by those skilled in the art, that certainmoieties, known to those skilled in the art as “pro-moieties”, forexample as described by H. Bundgaard in “Design of Prodrugs” (thedisclosure in which document is incorporated herein by reference) may beplaced on appropriate functionalities when such functionalities arepresent within the compounds defined in the first aspect. Therefore, ina further aspect, the invention provides a prodrug of a compound definedin the first aspect.

The compounds defined in the first aspect, their pharmaceuticallyacceptable salts or prodrugs, may exist in solvated or hydrated form.Therefore, in a further aspect, the invention provides a solvate orhydrate of a compound defined in the first aspect or a pharmaceuticallyacceptable salt thereof.

The compounds defined in the first aspect, their pharmaceuticallyacceptable salts, or solvates or hydrates, may exist in one or morepolymorphic form. Therefore, in a further aspect, the invention providesa polymorph of a compound defined in the first aspect or theirpharmaceutically acceptable salts, or a polymorph of a solvate orhydrate of a compound defined in the first aspect or a pharmaceuticallyacceptable salt thereof.

Hereinafter, compounds defined in the first aspect, their salts andprodrugs; any solvates or hydrates of any salt or prodrug; and anypolymorph of any compound, salt, solvate or hydrate are referred to as“compounds of the invention”. The term “compounds of the invention” alsoincludes all embodiments described for the first aspect.

The compounds of the invention may possess one or more chiral centresand so exist in a number of stereoisomeric forms. All stereoisomers andmixtures thereof are included in the scope of the present invention.Racemic compounds may either be separated using preparative HPLC orpreparative SFC and a column with a chiral stationary phase or resolvedto yield individual enantiomers utilising methods known to those skilledin the art. In addition, racemic intermediate compounds may be resolvedand used to prepare chiral compounds of the invention. In addition, thechiral compounds of the invention may be prepared by chiral synthesis.

In an embodiment, the compound of formula (I) is(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.

In an embodiment, the compound of formula (I) is(S)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.

The compounds of the invention may exist in one or more tautomericforms. All tautomers and mixtures thereof are included in the scope ofthe present invention. For example, a claim to 2-hydroxyquinolinyl wouldalso cover its tautomeric form, α-quinolinonyl.

The invention also includes all suitable isotopic variations of acompound of the invention. An isotopic variation of a compound of theinvention is defined as one in which at least one atom is replaced by anatom having the same atomic number but an atomic mass different from theatomic mass usually found in nature. Examples of isotopes that can beincorporated into compounds of the invention include isotopes ofhydrogen, carbon, nitrogen, oxygen, phosphorus, sulphur, fluorine andchlorine such as ²H, ³H, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁷O, ¹⁸O, ³⁵S, ¹⁸F and³⁶Cl, respectively. Certain isotopic variations of the invention, forexample, those in which a radioactive isotope such as ³H or ¹⁴C isincorporated, are useful in drug and/or substrate tissue distributionstudies. Tritiated, i.e., ³H, and carbon-14, i.e., ¹⁴C, isotopes areparticularly preferred for their case of preparation and detectability.Further, substitution with isotopes such as deuterium, i.e., ²H, mayafford certain therapeutic advantages resulting from greater metabolicstability, for example, increased in vivo half-life or reduced dosagerequirements and hence may be preferred in some circumstances. Isotopicvariations of the compounds of the invention can generally be preparedby conventional procedures such as by the illustrative methods or by thepreparations described in the Experimental section hereafter usingappropriate isotopic variations of suitable reagents.

Compounds of the invention may be prepared in a variety of ways. In thefollowing reaction schemes and hereafter, unless otherwise stated R¹ toR³ are as defined in the first aspect. These processes form furtheraspects of the invention.

Throughout the specification, general formulae are designated by Romannumerals (I), (II), (III), (IV) etc. Subsets of these general formulaeare defined as (Ia), (Ib), (Ic) etc. . . . (IVa), (IVb), (IVc) etc.

Compounds of general formula (I) may be prepared from compounds offormula (II) according to reaction scheme 1. Suitable reactionconditions comprise treating compounds of formula (II) with gaseoushydrogen chloride at low temperature (for example −78 deg C.) followedby treatment with methanolic ammonia.

The hydrochloride salt of compounds of formula (I) may be prepared bytreating compounds of formula (I) with methanolic hydrochloric acid.

Compounds of general formula (II) may be prepared from compounds offormula (III) according to reaction scheme 2. Suitable reactionconditions comprise mixing compounds of formula (III) with5,5,5′,5′-tetramethyl-2,2′-bi(1,3,2-dioxaborinane), potassium acetateand PdCl₂(dppf) in 1,4-dioxane at 130° C.

Compounds of general formula (III) may be prepared from compounds offormula (IV) according to reaction scheme 3. Suitable conditionscomprise treatment with sodium borohydride in ethanol.

Compounds of formula (IIIa), i.e. compounds of general formula (III)where the carbon atom attached to the hydroxy group is chiral, may beprepared according to the three-step procedure shown in Scheme 4.Treatment with an appropriate asymmetric hydrogenating agent gives anenantiomerically enriched mixture of alcohols (IIIb). Treatment of(IIIb) with chiral acid (V) gives diasteromeric mixture of esters (VI)which may be separated by chromatography or crystallisation.De-esterification reveals the desired chiral alcohol (IIIa).

Compounds of formula (IV) may be prepared via a number of methods. Forexample, Compounds of formula (IV) may be prepared from compounds offormula (VII) and (VIII) according to reaction scheme 5. Suitablereaction conditions comprise heating a solution of (VII), (VIII),xantphos, Pd₂(dba)₃ and a base (such as sodium tert-butoxide or cesiumcarbonate) in dry 1,4-dioxane at elevated temperature.

Alternatively compounds of formula (IV) may be prepared from compoundsof formula (IX) and (X) according to reaction scheme 6. Suitableconditions comprise treatment with NaHMDS in THF.

Compounds of formula (Xa), i.e. compounds of general formula (X) whereR³ is 3-chlorobenzyloxy or 3-pyridylmethoxy, may be prepared fromcompounds of formula (XI) according to reaction scheme 7. Suitableconditions comprise treating 3-chlorobenzyl alcohol or 3-pyridylmethylalcohol (respectively) with sodium hydride in a suitable solvent (eg.,DMF) at low temperature (e.g., 0° C.), followed by dropwise addition of(XI) in a suitable solvent.

Compound (XI) may be prepared from compounds of formula (XII) accordingto reaction scheme 8. Suitable reaction conditions comprise reacting(XII), zinc cyanide, tetramethylethylenediamine, Pd₂(dba)₃ and xantphosat elevated temperature (e.g., 120° C.)

Compound (XII) may be prepared from compound (XIII) according toreaction scheme 9. Suitable reaction conditions comprise reacting (XIII)in a suitable solvent (e.g., THF) with methyl magnesium chloride at 0°C.

Compound (XIII) may be prepared from compound (XIV) according toreaction scheme 10. Suitable reaction conditions comprise reacting (XIV)with oxalyl chloride/DMF to form the corresponding acyl chloride,followed by reaction with N,O-dimethylhydroxylamine hydrochloride andtrimethylamine.

Compound (XIV) is known in the art and is commercially available.

Alternatively compounds of formula (Xa) may be prepared from compound(XV) according to reaction scheme 11. Suitable conditions comprisereacting (XV) with 3-chlorobenzyl alcohol or 3-pyridylmethyl alcohol inthe presence of triphenylphosphine and(E)-bis(2-methoxyethyl)diazene-1,2-dicarboxylate or through alkylationconditions comprising for example reaction of (XV) with3-chlorobenzylbromide or 3-pyridylmethylbromide in presence of a basesuch as potassium carbonate.

Compound (XV) may be prepared from compound (XVI) according to reactionscheme 12. Suitable reaction conditions comprise treating (XVI) withpotassium ferrocyanide trihydrate, sodium carbonate and palladium (II)acetate in dimethylacetamide at elevated temperature (e.g., 140° C.).

Compound (XVI) is known in the art and is commercially available.

The compounds of the invention may be useful in treating diseases orconditions mediated by the KLK-5 pathway.

As used herein, “treat”, “treating” or “treatment” in reference to adisease or condition means: (1) to ameliorate the disease or conditionor one or more of the biological manifestations of the disease orcondition, (2) to interfere with (a) one or more points in thebiological cascade that leads to or is responsible for the disease orcondition or (b) one or more of the biological manifestations of thedisease or condition, (3) to alleviate one or more of the symptoms oreffects associated with the disease or condition, (4) to slow theprogression of the disease or condition or one or more of the biologicalmanifestations of the disease or condition, and/or (5) to diminish thelikelihood of severity of a disease or condition or biologicalmanifestations of the disease or condition.

The compounds of the invention will normally, but not necessarily, beformulated into pharmaceutical compositions prior to administration to apatient by an appropriate route. Accordingly, in another aspect, theinvention provides pharmaceutical compositions comprising a compound ofthe invention and one or more pharmaceutically-acceptable excipients.

As used herein, “pharmaceutically-acceptable excipient” means anypharmaceutically acceptable material present in the pharmaceuticalcomposition or dosage form other than the compound or compounds of theinvention. Typically, the material gives form, consistency andperformance to the pharmaceutical composition.

The pharmaceutical compositions of the invention typically contain onecompound of the invention. However, in certain embodiments, thepharmaceutical compositions of the invention contain more than onecompound of the invention. In addition, the pharmaceutical compositionsof the invention may comprise one or more additional pharmaceuticallyactive compounds.

Such pharmaceutical compositions of the invention may be prepared andpackaged in bulk form wherein a safe and effective amount of a compoundof the invention can be dispensed and then given to the patient such aswith powders or syrups. Alternatively, the pharmaceutical compositionsof the invention may be prepared and packaged as dosage forms whereineach physically discrete dosage form contains a safe and effectiveamount of a compound of the invention. Accordingly, in another aspect,the invention provides dosage forms comprising pharmaceuticalcompositions of the invention. Each discrete dosage form typicallycontains from 0.1 mg to 3000 mg of a compound of the invention.

The compositions of the invention will typically be formulated intodosage forms which are adapted for administration to the patient by thedesired route of administration. For example, dosage forms include thoseadapted for (1) oral administration such as tablets, capsules, caplets,pills, lozenges, powders, syrups, elixirs, suspensions, solutions,emulsions, sachets and cachets; (2) parenteral administration such assterile solutions, suspensions, implants and powders for reconstitution;(3) transdermal administration such as transdermal patches; (4) rectaland vaginal administration such as suppositories, pessaries and foams;(5) inhalation and intranasal such as dry powders, aerosols, suspensionsand solutions (sprays and drops); (6) topical administration such ascreams, ointments, lotions, solutions, pastes, sprays, foams and gels;(7) buccal and sublingual administration such as lozenges, patches,sprays, drops, chewing gums and tablets.

Suitable pharmaceutically-acceptable excipients will vary depending uponthe particular dosage form chosen. In addition, suitablepharmaceutically-acceptable excipients may be chosen for a particularfunction that they may serve in the composition. For example, certainpharmaceutically-acceptable excipients may be chosen for their abilityto facilitate the production of uniform dosage forms. Certainpharmaceutically-acceptable excipients may be chosen for their abilityto facilitate the production of stable dosage forms. Certainpharmaceutically-acceptable excipients may be chosen for their abilityto facilitate the carrying or transporting of the compound or compoundsof the invention once administered to the patient from one organ, orportion of the body, to another organ, or portion of the body. Certainpharmaceutically-acceptable excipients may be chosen for their abilityto enhance patient compliance. Certain pharmaceutically-acceptableexcipients may be chosen for their ability to facilitate the release ofthe compound of the invention at the appropriate rate to treat thecondition.

Suitable pharmaceutically-acceptable excipients include the followingtypes of excipients: diluents, tillers, binders, disintegrants,lubricants, glidants, granulating agents, coating agents, wettingagents, solvents, co-solvents, suspending agents, emulsifiers,sweeteners, flavouring agents, flavour masking agents, colouring agents,anticaking agents, humectants, chelating agents, plasticizers, viscosityincreasing agents, rate modifying agents, antioxidants, preservatives,stabilizers, surfactants and buffering agents. The skilled artisan willappreciate that certain pharmaceutically-acceptable excipients may servemore than one function and may serve alternative functions depending onhow much of the excipient is present in the formulation and what otheringredients are present in the formulation.

Skilled artisans possess the knowledge and skill in the art to enablethem to determine suitable pharmaceutically-acceptable excipients inappropriate amounts for use with the compounds of the invention. Inaddition, there are a number of resources that are available to theskilled artisan which describe pharmaceutically-acceptable excipientsand may be useful in selecting suitable pharmaceutically-acceptableexcipients. Examples include Remington's Pharmaceutical Sciences (MackPublishing Company), The Handbook of Pharmaceutical Additives (GowerPublishing Limited), and The Handbook of Pharmaceutical Excipients (theAmerican Pharmaceutical Association and the Pharmaceutical Press). Thepharmaceutical compositions of the invention may be prepared usingtechniques and methods known to those skilled in the art. Some of themethods commonly used in the art are described in Remington'sPharmaceutical Sciences (Mack Publishing Company).

In an embodiment, the dosage form is adapted for topical administration,such as creams, ointments, lotions, solutions, pastes, sprays, foams andgels.

Formulations suitable for topical administration include liquid orsemi-liquid preparations suitable for penetration through the skin tothe site of inflammation such as liniments, lotions, creams, ointmentsand pastes suitable for administration to the skin.

Lotions according to the present invention include those suitable forapplication to the skin. Lotions or liniments for application to theskin may include an agent to hasten drying and to cool the skin, such asan alcohol or acetone, and/or a moisturizer such as glycerol or an oilsuch as castor oil or arachis oil.

Creams, ointments or pastes according to the present invention aresemi-solid formulations of the active ingredient for externalapplication. They may be made by mixing the active ingredient infinely-divided or powdered form, alone or in solution or suspension inan aqueous or non-aqueous fluid, with the aid of suitable machinery,with a greasy or non-greasy base. The base may comprise hydrocarbonssuch as hard, soft or liquid paraffin, glycerol, beeswax, a metallicsoap; a mucilage; an oil of natural origin such as almond, corn,arachis, castor or olive oil; wool fat or its derivatives or a fattyacid such as steric or oleic acid together with an alcohol such aspropylene glycol or a macrogel. The formulation may incorporate anysuitable surface active agent such as an anionic, cationic or non-ionicsurfactant such as a sorbitan ester or a polyoxyethylene derivativethereof. Suspending agents such as natural gums, cellulose derivativesor inorganic materials such as siliceous silicas, and other ingredientssuch as lanolin, may also be included.

For topical administration, the compound of the invention may comprisefrom 0.001% to 10% w/w, for instance from 1% to 2% by weight of theformulation. It may however comprise as much as 10% w/w but preferablywill comprise less than 5% w/w, more preferably from 0.1% to 3% w/w ofthe formulation.

It will be appreciated that the invention includes the following furtheraspects. The diseases and conditions described above extend, whereappropriate, to these further aspects. In addition, the embodimentsdefined above in relation to the first aspect extend to these furtheraspects.

-   -   i) The use of a compound of the invention in the manufacture of        a medicament for treating a disease or condition mediated by the        KLK-5 pathway. In an embodiment, the disease or condition is        selected from the group consisting of: Netherton syndrome,        rosacea, atopic dermatitis, psoriasis and itch.    -   ii) A method of treating a disease or condition mediated by the        KLK-5 receptor in a human comprising administering an effective        amount of a compound of the invention. In an embodiment, the        disease or condition is selected from the group consisting of:        Netherton syndrome, rosacea, atopic dermatitis, psoriasis and        itch.    -   iii) A pharmaceutical composition comprising a) a compound of        the invention and b) one or more pharmaceutically acceptable        excipients.    -   iv) A pharmaceutical composition comprising a) 0.05 to 3000 mg        of a compound of the invention and b) 0.1 to 100 g of one or        more pharmaceutically acceptable excipients.    -   v) A pharmaceutical composition for the treatment of a disease        or condition mediated by the KLK-5 pathway. In an embodiment,        the disease or condition is selected from the group consisting        of: Netherton syndrome, rosacea, atopic dermatitis, psoriasis        and itch.    -   vi) A compound of the invention for use in therapy.    -   vii) A compound of the invention for use in the treatment of a        disease or condition mediated by the KLK-5 pathway. In an        embodiment, the disease or condition is selected from the group        consisting of: Netherton syndrome, rosacea, atopic dermatitis,        psoriasis and itch.

Supporting Compounds

Compounds of the invention and intermediates have been named usingeither a) ACD/Name PRO 6.02 chemical naming software (Advanced ChemistryDevelopment Inc., Toronto, Ontario, M5H2L3, Canada); or b)MarvinSketch.NET.5.11.4 (ChemAxon Kft. Záhony u. 7, Building HX 1031Budapest, Hungary)

ABBREVIATIONS

-   ACN—acetonitrile-   CHAPS—cholamidopropyl)dimethylammonio]-1-propanesulfonate)-   DMAP—N,N-dimethylpyridin-4-amine-   DMF—N,N-dimethylformamide-   DMSO—dimethylsulphoxide-   DMAP—4-dimethylaminopyridine-   EDC—1-ethyl-3-(3-dimethylaminopropyl)carbodiimide-   ES—electrospray-   GCMS—gas chromatography mass spectrometry-   HPLC—High Pressure Liquid Chromatography-   IPA—isopropyl alcohol-   LCMS—liquid chromatography mass spectrometry-   MS—mass spectrometry-   rt—retention time-   SFC—supercritical fluid chromatography-   TFA—trifluoroacetic acid-   THF—tetrahydrofuran-   UPLC—Ultra Performance Liquid Chromatography

LCMS Methods

Method 1:

Analytical HPLC was conducted on a X-Select CSH C18 XP column (2.5 μm30×4.6 mm id) eluting with 0.1% formic acid in water (solvent A) and0.1% formic acid in acetonitrile (solvent B), using the followingelution gradient 0-3 minutes: 5% to 100% B, 3-4 minutes 100% B, at aflow rate of 1.8 ml/minute at 40° C. The mass spectra (MS) were recordedon a Waters ZQ mass spectrometer (scan 200-900 uma) using electrospraypositive ionisation [ES+ to give MH+ molecular ions] or electrospraynegative ionisation [ES− to give (M-H)− molecular ions] modes with a 20Vcone voltage.

Method 2:

Analytical HPLC was conducted on a X-Select CSH C18 XP column (2.5 μm30×4.6 mm id) eluting with 0.1% formic acid in water (solvent A) and0.1% formic acid in acetonitrile (solvent B), using the followingelution gradient 0-6 minutes: 5% to 100% B, 6-7 minutes 100% B, at aflow rate of 1.8 ml/minute at 40° C. The mass spectra (MS) were recordedon a Waters ZQ mass spectrometer (scan 200-900 uma) using electrospraypositive ionisation [ES+ to give MH+ molecular ions] or electrospraynegative ionisation [ES− to give (M-H)− molecular ions] modes with a 20Vcone voltage.

Method Description A Column: Acquity BEH C18 (50 mm X 2.1 mm, 1.7 μm)Mobile Phase: A: 0.05% Formic acid in water; B: 0.05% Formic acid in ACNTime (min)/% B; 0/3, 0.4/3, 3.2/98, 3.8/98, 4.2/3, 4.5/3 Column Temp:35° C. Flow Rate: 0.6 mL/min B Column: Acquity BEH C18 (50 mm X 2.1 mm,1.7 μm) Mobile Phase: A: 0.1% Formic acid in water; B: 0.1% Formic acidin ACN Time (min)/% B: 0/3, 0.4/3, 3.2/98, 3.8/98, 4.2/3, 4.5/3 ColumnTemp: 35° C. Flow Rate: 0.6 mL/min D Column: XBridge C18 (50 mm × 4.6mm, 2.5 μm) Mobile Phase: A: 5 mM Ammonium Bicarbonate in water (pH 10).B: 100% ACN Gradient: Time (min)/1% B: 0/5, 0.5/5, 1.5/15, 7/98, 9/98,9,5/5, 10/5 Column Temp: 35° C., Flow Rate: 1.3 ml/min I Column: AcquityBEH C18 (50 mm × 2.1 mm, 1.7 um) Mobile Phase: A: 5 mM AmmoniumBicarbonate in water (pH-10); B: ACN Time (min)/% B: 0/3, 0.4/3, 7.5/98,9,5/98, 9.6/3, 10/3 Column Temp: 35° C., Flow Rate: 0.6 ml/min J Column:Acquity BEH C18 (50 mm × 2.1 mm, 1.7 um) Mobile Phase: A: 0.1% FormicAcid in water; B: 0.1% Formic Acid in ACN Time (min)/% B: 0/3, 0,4/3,4/98, 4.5/98, 5/3, 5.5/3 Column Temp: 35° C., Flow Rate: 0,45 mL/min KColumn: Acquity BEH C18 (50 mm × 2.1 mm, 1.7 um) Mobile Phase: A: 0.1%Formic Acid in water; B: 0.1% Formic Acid in ACN Time (min)/% B: 0/3,0.4/3, 2.0/98, 3.4/98, 3.5/3, 4.0/3 Column Temp: 35° C., Flow Rate: 0.6mL/min L Column: Acquity BEH C18 (50 mm × 2.1 mm, 17 um) Mobile Phase:A: 5 mM Ammonium Bicarbonate in water (pH-10); B: ACN Time (min)/% B:0/3, 0.4/3, 2.5/98, 3.4/98, 3.5/3, 4.0/3 Column Temp: 35° C., Flow Rate:0.6 ml/min M Column: Acquity BEH C18 (100 mm X 2.1 mm, 1.7 μm) MobilePhase: A: 0.05% TFA in water; B: ACN Time (min)/% B: 0/3, 0.4/3, 7.5/98,9.5/98, 9.6/3, 10/3 Column Temp: 35° C.; Flow Rate: 0.45 mL/min NColumn: Acquity BEH C18 (100 mm X 2.1 mm, 1.7 μm) Mobile Phase: A: 0.05%TFA in water; B: ACN Time (min)/% B: 0/3, 0.4/3, 3.5/98, 4.5/98, 5.0/3,5.5/3. Column Temp: 35° C.; Flow Rate: 0.45 mL/min O Column: Acquity BEHC18 (50 mm × 2.1 mm, 1.7 um) Mobile Phase: A: 0.05% Formic Acid inWater; B: 0,05% Formic Acid in ACN Gradient Time (min)/% A: 0/97,0.4/97, 4.0/2, 4.5/2, 5/97, 5.5/97 Column Temp: 35° C., Flow Rate: 0.45ml/min

GCMS Methods

Method Description A Column: ZB-5MS (30 mm X 0.32 mm, 1 μm) He = 2.0mL/min; Inj = 230° C.; Program: 100° C./1 min; 20 *C./min/310° C./5.5min.

UPLC/HPLC Methods

Method Description C Column: Acquity BEH C18 (100 mm X 2.1 mm, 1.7 μm)Mobile Phase: A 0.1% TFA in water, B: 0.1% TFA in ACN Time (min)/% B:0/3, 8.5/100, 9.0/100, 9.5/3, 10/3. Column Temp: 50° C.; Flow Rate: 0.55mL/min

Chiral HPLC/SFC Methods

Method Description A Column: CHIRALPAK AD-H (250 mm X 4.6 mm, 5 μm)Eluent: A: CO₂ = 85%; B: methanol = 15%; Back pressure: 100 bar; Temp:24.5° C.; Flow Rate: 3 g/min B Column: CHIRALCEL OD-H (250 mm X 4.6 mm,5 μm) Eluent: A: CO₂ = 75%; B: 30 mM methanolic ammonia in IPA = 25%;Back pressure: 100 bar; Temp: 25° C.; Flow Rate: 3 g/min C Column:CHIRALCEL OD-H (250 mm X 4.6 mm, 5 μm) Eluent: A: CO₂ = 75%; B: 0.5%diethylamine in methanol = 25%; Back pressure: 100 bar; Temp: 24.8° C.;Flow Rate: 3 g/min D Column: CHIRALCEL, OD-H (250 mm X 4.6 mm, 5 μm)Eluent: A: CO₂ = 75%; B: 0.5% isopropyl amine in IPA = 25%; Backpressure: 100 bar; Temp 25° C.; Flow Rate: 3 g/min

Supporting Compounds/Intermediates

In the procedures that follow, after each starting material, referenceto an intermediate is typically provided. This is provided merely forassistance to the skilled chemist. The starting material may notnecessarily have been prepared from the batch referred to.

Compound 14-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamideHydrochloride Salt

4-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 1, 150 mg, 0.354 mmol) was dissolved in ethanol (20 mL) ina sealed tube and cooled to −78° C. Hydrogen chloride (g) was slowlybubbled through this solution for 10 min. The reaction was allowed torise to ambient temperature and to stand overnight at that temperature.The resulting solution was concentrated under reduced pressure using awater bath heated at 30° C. The imidate was dissolved in methanolicammonia (7N, excess) and stirred overnight in a sealed tube. Thereaction was concentrated under reduced pressure and the residue wastaken up in water, methanol and ethyl acetate to eliminate the sideproducts. The residual white powder was dissolved in hydrochloric acid(1 M) and concentrated under reduced pressure. The residue was dried at40° C. and reduced pressure for 3 h to give the title compound (20 mg).¹H NMR (D₆-DMSO): δH 9.26 (s, 2H), 9.12 (s, 2H), 8.91 (s, 1H), 8.78 (d,J=4.6 Hz, 1H), 8.31 (d, J=7.2 Hz, 1H), 8.08 (s, 1H), 7.80 (d, J=6.6 Hz,2H), 7.59 (d, J=8.0 Hz, 1H), 7.49 (m, 2H), 7.29 (d, J=8.0 Hz, 1H), 5.41(m, 3H), 3.27 (m, 1H), 3.18 (m, 1H). LCMS: retention time 1.59 min, MH⁺442 (Method 1).

Intermediate 14-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile

4-(2-(2-Bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 2, 200 mg, 0.419 mmol)5,5,5′,5′-tetramethyl-2,2′-bi(1,3,2-dioxaborinane) (284 mg, 1.257 mmol)and PdCl2(dppf) (3.68 mg, 5.03 μmol) were mixed in 1,4-dioxane (15 mL)in a sealed tube. This suspension was de-gassed and back-filled withnitrogen. Potassium acetate (82 mg, 0.838 mmol) was added, the reactionvessel was sealed and heated to 130° C. under microwave irradiation for25 min. The reaction mixture was filtered through a CELITE bed and thefiltrate was concentrated in vacuo. The residue was directly loaded ontoa 40 g silica column and eluted with 0-30% (ethyl acetate/ethanol 3:1)in cyclohexane. The appropriate fractions were combined and concentratedunder reduced pressure. The residue was taken up in acetonitrile andfiltered to afford the title compound as a white solid (150 mg). ¹H NMR(D₆-DMSO) includes: δH 9.15 (s, 1H), 8.74 (d, J=1.7 Hz, 1H), 8.60 (dd,J=4.7 Hz, J=1.5 Hz, 1H), 8.06 (s, 1H), 7.93 (dt, J=7.8 Hz, J=1.9 Hz×2,1H), 7.80 (m, 2H), 7.56 (m, 1H), 7.48 (m, 2H), 7.26 (d, J=8.0 Hz, 1H),5.38 (m, 3H), 3.25 (m, 1H). LCMS: retention time 2.46 min, MH⁺ 425(Method 1).

Intermediate 24-(2-(2-Bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile

To a solution of4-(2-(2-bromo-4-(trifluoromethyl)phenyl)acetyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 3, 480 mg, 1.010 mmol) in ethanol was added sodiumborohydride (38.2 mg, 1.01 mmol) and the reaction was stirred for 1 h at20° C. The experiment was quenched with hydrochloric acid (1 M). Themixture was stirred for 5 min at ambient temperature, then sodiumhydroxide solution (1 M) was added until the pH reached 8. The resultingsolution was extracted with ethyl acetate, the organic phase dried oversodium sulphate and filtered. The filtrate was concentrated in vacuo.The residue was loaded onto a 40 g silica column and eluted with agradient of 0-30% (ethyl acetate/ethanol 3:1) in cyclohexane. Theappropriate fractions were combined and concentrated in vacuo to givethe title compound as a cream solid (200 mg). ¹H NMR (D₆-DMSO): δH 8.72(d, J=1.7 Hz, 1H), 8.59 (dd, J=4.8 Hz. J=1.6 Hz, 1H), 7.98 (s, 1H), 7.91(dt, J=7.9 Hz, J=1.9 Hz×2, 1H), 7.71 (m, 2H), 7.53 (d, J=8.0 Hz, 1H),7.48 (dd, J=7.9 Hz, J=4.8 Hz, 1H), 7.33 (s, 1H), 7.08 (d, J=8.0 Hz, 1H),5.77 (d, J=5.1 Hz, 1H), 5.35 (d, J=11.8 Hz, 1H), 5.28 (d, J=12.0 Hz,1H), 3.08 (m, 2H). LCMS: retention time 2.55 min, MH⁺ 477/479 (Method1).

Intermediate 34-(2-(2-Bromo-4-(trifluoromethyl)phenyl)acetyl)-2-(pyridin-3-ylmethoxy)benzonitrile

The reaction was performed in two sealed tubes of equal charge (450 mgof 4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile in each). A solution of2-bromo-1-iodo-4-(trifluoromethyl)benzene (1391 mg, 3.57 mmol),4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile (Intermediate 4, 900 mg,3.57 mmol), xantphos (74.3 mg, 0.128 mmol), Pd2(dba)3 (49.0 mg, 0.054mmol) and sodium tert-butoxide (1029 mg, 10.70 mmol) in dry 1,4-dioxane(8 ml) was heated at 80° C. in a Biotage Initiator microwave for 60 min.The reaction was filtered and the filtrate was concentrated underreduced pressure. The residue was dissolved in ethyl acetate and washedwith water. The organic phase was dried over sodium sulphate andfiltered. The filtrate was concentrated in vacuo. The residue was loadedonto an 80 g silica column and eluted with a gradient of 0-20% (ethylacetate/ethanol 3:1) in cyclohexane. The appropriate fractions werecombined and concentrated in vacuo to give the title compound as a creamsolid (510 mg). ¹H NMR (D₆-DMSO): δH 8.75 (s, 1H), 8.60 (d, J=3.8 Hz,1H), 8.03 (m, 2H), 7.94 (m, 2H), 7.86 (d, J=8.0 Hz, 1H), 7.80 (d, J=7.6Hz, 1H), 7.66 (d, J=7.8 Hz, 1H), 7.49 (dd, J=7.6 Hz, J=4.9 Hz, 1H), 5.49(s, 2H), 4.80 (s, 2H). LCMS: retention time 2.71 min, MH⁺ 475/477(Method 1).

Intermediate 4 4-Acetyl-2-(pyridin-3-ylmethoxy)benzonitrile

4-Acetyl-2-hydroxybenzonitrile (Intermediate 5, 1000 mg, 6.21 mmol) wasadded to pyridin-3-ylmethanol (745 mg, 6.83 mmol), triphenylphosphine(2441 mg, 9.31 mmol) and(E)-bis(2-methoxyethyl)diazene-1,2-dicarboxylate (2180 mg, 9.31 mmol).The reaction was stirred at 20° C. for 3 days. The reaction mixture wasconcentrated in vacuo, the residue was dissolved in ethyl acetate andwashed with sodium hydroxide solution (1N) and water. The organic phasewas dried over sodium sulphate and filtered. The filtrate wasconcentrated in vacuo and the residue loaded onto an 80 g silica columnand eluted with a gradient of 0-20% (ethyl acetate/ethanol 3:1) incyclohexane. The appropriate fractions were combined and concentrated invacuo to give the title compound as a white solid (900 mg). ¹H NMR(D₆-DMSO): δH 8.74 (s, 1H), 8.60 (d, J=3.4 Hz, 1H), 7.95 (m, 2H), 7.79(s, 1H), 7.70 (d, J=8.0 Hz, 1H), 7.49 (dd, J=7.7 Hz, J=4.8 Hz, 1H), 5.45(s, 2H), 2.66 (s, 3H). LCMS: retention time 1.48 min, MH⁺ 253 (Method1).

Intermediate 5 4-Acetyl-2-hydroxybenzonitrile

Under inert conditions, potassium ferrocyanide trihydrate (1.179 g, 2.79mmol) and sodium carbonate (1.971 g, 18.60 mmol) were ground to a finepowder and dried under vacuum at 60° C. for 3 h. A flask was chargedwith 1-(4-bromo-3-hydroxyphenyl)ethanone (2 g, 9.30 mmol),dimethylacetamide (20 mL, 9.30 mmol) and the potassiumferrocyanide/sodium carbonate mixture then evacuated and filled withnitrogen (×2). Palladium(II) acetate (0.104 g, 0.465 mmol) was added andthe reaction was heated at 140° C. for 2 h. The reaction mixture wascooled to ambient temperature and diluted with ethyl acetate (20 mL).The resulting slurry was filtered and the filtrate was washed with ethylacetate. Hydrochloric acid (1 M) was added to the filtrate and theproduct was extracted with ethyl acetate. The organic layer was driedover sodium sulphate and filtered. The solution was treated withcharcoal and filtered through a silica bed to afford a yellow solution.The solvent was evaporated and the residual pale yellow solid (1.1 g)was used in next reaction without further purification. ¹H NMR(D₆-DMSO): δH 11.48 (s, 1H), 7.79 (d, J=8.0 Hz, 1H), 7.50 (m, 2H), 2.58(s, 3H). LCMS: retention time 1.73 min, MH⁺ 160 (Method 1).

Compound 2(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamideHydrochloride Salt

To a stirred suspension of(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide(Compound 3, 21 g, 47.51 mmol) in methanol (42 mL), was added 4N HCl inmethanol (42 mL) at 0° C. under inert atmosphere (a clear solution wasobserved). After 30 minutes stirring, methanol was evaporated underreduced pressure and the residue was freeze-dried for 9 days. Theresidue was stirred in acetonitrile (200 mL) for 24 h and the solidisolated by filtration. The solid was dissolved in methanol (50 mL) anddiethyl ether (800 mL) added slowly. The solid was isolated byfiltration and freeze-drying for 48 h to give the title compound (20.3g; 99.4% ee) as an off-white solid. ¹H NMR (400 MHz, DMSO-d₆): δ ppm9.25 (br s, 2H; D₂O exchangeable), 9.16 (br s, 2H; D₂O exchangeable),8.93 (s, 1H), 8.78 (d, J=5.0 Hz, 1H), 8.36 (d, J=7.9 Hz, 1H), 8.08 (s,1H), 7.88-7.75 (m, 2H), 7.58 (d, J=7.7 Hz, 1H), 7.52-7.44 (m, 2H), 7.28(d, J=7.9 Hz, 1H), 5.45-5.34 (m, 3H), 3.33-3.23 (m, 1H), 3.21-3.11 (m,1H). LCMS (ESI): retention time 2.45 min, MH⁺ 442; 99.3% (method N).UPLC: retention time 3.56 min, 98.90% (method C). Chiral HPLC: retentiontime 3.77 min, 99.71% (method C). SOR=+80.42 (c=0.5 in MeOH).

Compound 3(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

A freshly prepared ammonia solution in methanol (approx. 7 M insolution; 1.5 L) was added to crude methyl(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidate(Intermediate 6, 50 g) at 0° C. The reaction was allowed to stir at roomtemperature. After 24 h ammonia solution in methanol (500 mL) was addedand stirred at room temperature for 48 h. The solid was isolated byfiltration, washed with ammonia solution in methanol (300 mL) and driedunder vacuum. The solid was taken in water (1 L) and stirred for 3 h.The solid was filtered off and dried under vacuum to afford the titlecompound (21 g) as an off-white solid. ¹H NMR (400 MHz, DMSO-d6; VT-90°C.): δ ppm 8.69 (s, 1H), 8.54-8.53 (d, J=3.5 Hz, 1H), 8.04 (s, 1H), 7.86(d, J=7.9 Hz, 1H), 7.71 (d, J=7.0 Hz, 1H), 7.51 (d, J=7.9 Hz, 1H),7.47-7.34 (m, 2H), 7.29 (s, 1H) 7.10 (d, J=7.9 Hz, 1H), 5.30 (dd,J=10.1, 3.7 Hz, 1H), 5.21 (s, 2H), 3.19-3.29 (m, 1H), 3.14-3.09 (m, 1H).LCMS (ESI): retention time 3.60 min; MH⁺ 442; 95.5% (method M). UPLC:retention time 3.63 min, 97.88% (method C).

Intermediate 6 Methyl(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidate

A stirred solution of(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 7, 40 g, 94.33 mmol) in methanol (1.6 L) was purged withdry HCl gas at −10° C. until complete saturation was observed (dry HCgas was purged for ˜9 h). The reaction was allowed to stir at roomtemperature for 16 h. The reaction solution was concentrated underreduced pressure (below −35° C.) under inert atmosphere conditions toafford the crude title compound (50 g) as a pale yellow sticky solid,which was directly taken for next reaction. LCMS (ESI): retention time1.46 min; MH⁺ 457; 78.2% (method K).

Intermediate 7(R)-4-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred and degassed solution of(R)-4-(2-(2-bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 8, 125 g, 0.262 mol) and bis(neopentyl glycolato)diboron(2% g, 1.31 mol) in 1,4-dioxane (3.125 L, 25 vol) tert-butyldiphenylphosphine (6.48 g, 26.2 mmol) and Pd(OAc)₂ (8.82 g, 13.10 mmol)were added sequentially and the mixture degassed for 10 min. Finallypotassium acetate (103 g, 1.048 mol) was added and the mixture degassedfor 10 min. The reaction was stirred at 75° C. for 3 h. The reactionmixture was filtered through a CELITE pad with the aid of ethyl acetate(2.5 L). The filtrate was washed with water (5×2 L), brine (2×2 L) driedover Na₂SO₄, filtered and kept aside for 12 h. The precipitated solidwas isolated by filtration and dried under vacuum to afford 85 g of thetitle compound (96% pure) as an off-white solid.

Pd-scavenger treatment: To a clear solution of(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile(106 g) in 3% methanol in ethyl acetate (3 L) at 65° C., was addedSiliamet®-DMT (10.6 g; 0.1 w/w) and stirred for 3 h at same temperature.The resultant hot heterogeneous mixture was filtered through a CELITEpad. The filtrate was concentrated under reduced pressure. The resultantresidue was stirred in acetonitrile (1 L) overnight, the solid isolatedby filtration and dries to give the title compound (85 g) as anoff-white solid.

HNMR (400 MHz, DMSO-d₆): δ ppm 9.12 (s, 1H), 8.73 (s, 1H), 8.59 (d,J=4.6 Hz, 1H), 8.06 (s, 1H), 7.92 (d, J=7.9 Hz, 1H), 7.79-7.77 (m, 2H),7.54 (s, 1H), 7.51-7.44 (m, 2H), 7.26 (d, J=8.1 Hz, 1H), 5.42-5.30 (m,3H), 3.28-3.22 (m, 1H), 3.17-3.09 (m, 1H). LCMS (ESI): retention time1.87 min; MH⁺ 425; 99.63% (method K). UPLC: 99.15% retention time 4.48min (method C). Chiral HPLC: 99.99% retention 4.28 min (method B).

Intermediate 8(R)-4-(2-(2-Bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred solution of(R)-2-(2-bromo-4-(trifluoromethyl)phenyl)-1-(4-cyano-3-(pyridin-3-ylmethoxy)phenyl)ethyl(S)-2-acetoxy-2-phenylacetate (Intermediate 9, 230 g, 352.2 mmol) inmethanol (2.3 L) was added potassium carbonate (24.3 g, 176 mmol) andthe reaction mixture stirred at 35° C. for 30 min. The reaction solventwas evaporated under reduced pressure. The residue was dissolved inethyl acetate (2.5 L), washed with water (2 L), brine (2 L), dried oversodium sulphate and concentrated under reduced pressure. The residue wastriturated with n-pentane (500 mL) for 1 h, the solid isolated byfiltration and dried under vacuum to afford the title compound (155 g,92% yield: 99.35% ee) as a pale yellow solid. ¹HNMR (400 MHz, DMSO-d₆):δ ppm 8.71 (d, J=1.8 Hz, 1H), 8.58 (dd, J=4.7, 1.4 Hz, 1H), 7.95 (s,1H), 7.91-7.89 (m, 1H), 7.74-7.65 (m, 2H), 7.52 (d, J=7.9 Hz, 1H),7.48-7.46 (m, 1H), 7.32 (s, 1H), 7.08 (d, J=7.9 Hz, 1H), 5.75 (br s,1H), 5.37-5.25 (m, 2H), 4.93 (br s, 1H), 3.12-3.06 (m, 2H). LCMS (ESI):retention time 2.27 min; MH⁺ 477; 98.62% (method B). Chiral HPLC:99.67%, retention time 9.13 min (method A).

Intermediate 9(R)-2-(2-Bromo-4-(trifluoromethyl)phenyl)-1-(4-cyano-3-(pyridin-3-ylmethoxy)phenyl)ethyl(S)-2-acetoxy-2-phenylacetate

To a stirred solution of(R)-4-(2-(2-bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 10, 300 g, 0.628 mol) in THF (3 L), were added(S)-(+)-O-acetyl-mandelic acid (220 g, 1.132 mol), EDC·HCl (264 g, 1.382mol) and DMAP (23 g, 188.6 mmol) at room temperature and continuedstirring for 4 h. The reaction was diluted with ethyl acetate (2 L),washed with water (2×2 L), brine (2 L), dried over anhydrous sodiumsulphate and concentrated under reduced pressure. The residue waspurified by silica gel column chromatography (silica 100-200 mesh)eluting with 45% ethyl acetate in petroleum ether to afford thediastereomeric mixture (340 g) as a pale yellow solid. HPLC: 61.8%desired diastereomer (retention time 5.85 min, method C) and 18.9% otherdiastereomer (retention time 5.74 min, method C). The diastereomericmixture (340 g) in isopropanol (10.2 L, 30 volumes) was heated at 68° C.to get a clear solution. Then the solution was allowed to cool to roomtemperature, seeded with the desired product (obtained from a previousbatch) and left aside for 18 h. The precipitated solid was isolated byfiltration, washed with isopropanol (3×300 mL), n-pentane (3×300 mL) anddried under vacuum to afford diastereomerically pure title compound (190g) as a pale yellow solid. ¹H NMR (400 MHz, DMSO-d₆): δ ppm 8.73 (s,1H), 8.61-8.60 (m, 1H), 7.92 (d, J=7.9 Hz, 1H), 7.84-7.76 (m, 2H), 7.49(dd, J=7.7, 4.8 Hz, 1H), 7.44-7.25 (m, 8H), 7.18 (d, J=7.9 Hz, 1H),6.05-6.03 (m, I1H), 5.94 (s, 1H), 5.42-5.29 (m, 2H), 3.27-3.25 (m, 2H),2.07 (s, 3H). LCMS (ESI): retention time 2.46 min, MH⁺ 653; 97% (methodL). HPLC: 95.67% retention time 5.87 min (method C).

Intermediate 10(R)-4-(2-(2-Bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred solution of4-(2-(2-bromo-4-(trifluoromethyl)phenyl)acetyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 11, 300 g, 0.632 mol) in DMF:iso-propanol:H₂O (3 L:3 L:300mL) mixture, were added potassium formate (266 g, 3.160 mol) andRuCl[(R,R)-Tsdpen]mesitylene (7.08 g, 11.39 mmol) and the reactionstirred for 16 h at room temperature under a nitrogen atmosphere. Theiso-propanol was removed under reduced pressure. The resultant reactionmixture was poured into ice cold water. The resulting gummy solid wasisolated by filtration, washed with cold water (6×1 L) and dried. Theobtained free solid was washed with 10% diethyl ether in pentane (3×400mL) and dried to afford the title compound (300 g, 99% yield; 69.27% cc)as a yellow solid. ¹H NMR (400 MHz, DMSO-d₆): δ ppm 8.71 (d, J=1.8 Hz,1H), 8.58 (dd, J=4.7, 1.4 Hz, 1H), 7.95 (s, 1H), 7.91-7.89 (m, 1H),7.74-7.65 (m, 2H), 7.52 (d, J=7.9 Hz, 1H), 7.48-7.46 (m, 1H), 7.32 (s,1H), 7.08 (d, J=7.9 Hz, 1H), 5.75 (br s, 1H), 5.37-5.25 (m, 2H), 4.93(br s, 1H), 3.12-3.06 (m, 2H). LCMS (ESI): retention time 2.21 min; MH⁺477, 93.1% (method B). Chiral HPLC: retention time 16.4 min; 84.54%(method A).

Intermediate 114-(2-(2-Bromo-4-(trifluoromethyl)phenyl)acetyl)-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred solution of 4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 12, 70 g, 278 mmol) and2-bromo-1-iodo-4-(trifluoromethyl)benzene (116.3 g, 333 mmol) in1,4-dioxane (1.05 L), cesium carbonate (181 g, 556 mmol) was added andthe mixture degassed for 10 min. To this, Xantphos (8.64 g, 16.7 mmol)was added and the mixture degassed for 10 min. Pd₂(dba) (7.63 g, 8.33mmol) were added and the mixture degassed for 10 min. The reactionmixture was heated at 90° C. for 4 h. The reaction mixture was filteredthrough a CELITE pad and washed with ethyl acetate (200 mL). Thefiltrate was diluted with water (200 mL), and extracted with ethylacetate (2×1 L). The organic phase was dried over Na₂SO₄ andconcentrated. The obtained crude product was purified by silica gelcolumn chromatography (silica 100-200 mesh), eluting with 40% ethylacetate in petroleum ether to afford a yellow solid (55 g). To a stirredsolution of 4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile (Intermediate12, 350 g, 1.38 mol) and 2-bromo-1-iodo-4-(trifluoromethyl)benzene(581.6 g, 1.66 mol) in 1,4-dioxane (5.25 L), cesium carbonate (905.2 g,2.77 mol) was added and the mixture degassed for 10 min. To this,Xantphos (43.2 g, 83.3 mmol) was added and the mixture degassed for 10min. Pd₂(dba)₃ (38.1 g, 41.6 mmol) were added and the mixture degassedfor 10 min. The reaction mixture was heated at 90° C. for 4 h. Thereaction mixture was filtered through a CELITE pad and washed with ethylacetate (3 L). The filtrate was diluted with water (2 L), and extractedwith ethyl acetate (2×4 L). The combined organic layer was dried overanhydrous Na₂SO₄ and concentrated under vacuum. The obtained crudeproduct was purified by silica gel column chromatography (silica 100-200mesh), eluting with 40% ethyl acetate in petroleum ether to afford ayellow solid (325 g). The solids were combined and washed with diethylether (500 mL) to afford the title compound (370 g, 46% combined yield)as a pale yellow solid.

¹HNMR (400 MHz, CDCl₃): δ ppm 8.71 (d, J=1.8 Hz, 1H), 8.63 (dd. J=4.7,1.2 Hz, 1H), 7.92-7.83 (m, 2H), 7.78-7.75 (m, 1H), 7.73-7.69 (m, 1H),7.67 (s, 1H), 7.58 (d, J=7.9 Hz, 1H), 7.40-7.34 (m, 2H), 5.30 (s, 2H),4.49 (s, 2H); LCMS (ESI): retention time 2.25 min, MH⁺ 475, 99.1%(method K).

Intermediate 12 4-Acetyl-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred suspension of sodium hydride (60% in mineral oil; 215 g,5.36 mol) in DMF (3 L) at 0° C. was added pyridin-3-ylmethanol (627 ml,6.44 mol) drop-wise over 30 min. The resultant mixture was stirred atroom temperature for 30 min. To this mixture, a solution of4-acetyl-2-fluorobenzonitrile (Intermediate 13, 350 g, 2.15 mol) in DMF(500 mL) was added drop-wise at 0° C. The reaction was then allowed tostir at room temperature for 3 h. Chilled water (7 L) was added. Thesolid formed was isolated by filtration, washed with diethyl ether (2.5L) and dried under vacuum to afford the title compound (450 g) as alight brown solid, which was directly taken for next reaction withoutfurther purification.

¹H NMR (400 MHz, CDCl₃): δ ppm 8.71 (s, 1H), 8.63-8.62 (m, 1H),7.89-7.87 (m, 1H), 7.72 (d, J=7.9 Hz, 1H), 7.64 (s, 1H), 7.61-7.59 (m,1H), 7.38-7.36 (m, 1H), 5.29 (s, 2H), 2.63 (s, 3H). LCMS (ESI):retention time 1.78 min, MH⁺ 253, 76% (method J).

Intermediate 13 4-Acetyl-2-fluorobenzonitrile

To a stirred solution of 1-(4-bromo-3-fluorophenyl)ethan-1-one (450 g,2.07 mol) in DMF (3.6 L) in an autoclave, zinc cyanide (607.5 g, 5.18mol) and then tetramethylethylenediamine (TMEDA, 342 ml, 2.07 mol) wereadded and the mixture degassed with argon for 10 min. To this, Pd₂(dba)₃(56.7 g, 62.1 mmol) and Xantphos (36 g, 62.1 mmol) were added anddegassed again with argon for 10 min. The reaction mixture was heated to120° C. and stirred for 4 h. The reaction was filtered through a CELITEpad. The filtrate was diluted with water (6 L) and extracted with ethylacetate (2×5 L). The combined organic layers were washed with brine (2L) and concentrated under reduced pressure to afford the crude productas a brown gum. To a stirred solution of1-(4-bromo-3-fluorophenyl)ethan-1-one (430 g, 1.98 mol) in DMF (3.44 L)in an autoclave, zinc cyanide (580.6 g, 4.95 mol) andtetramethylethylenediamine (TMEDA, 327 ml, 1.98 mol) were added and themixture degassed with argon for 10 min. To this, Pd₂(dba)₃ (54.2 g, 59.4mmol) and Xantphos (34.4 g, 59.4 mmol) were added and the mixturedegassed again with argon. The reaction mixture was heated to 120° C.and stirred for 4 h. The reaction was filtered through a CELITE pad. Thefiltrate was diluted with chilled water (5 L) and extracted with ethylacetate (2×3 L). The combined organic layers were washed with brine (1.5L), dried over sodium sulphate and concentrated under reduced pressureto afford the crude product.

The crude materials from both the batches were combined and purified bysilica gel column chromatography (silica 100-200 mesh) eluting with agradient of ethyl acetate in petroleum ether (25-50% ethyl acetate) toafford the title compound (630 g, 94%) as a yellow solid.

¹HNMR (400 MHz, CDCl₃): δ ppm 7.84-7.80 (m, 1H), 7.79-7.73 (m, 2H), 2.64(s, 3H). GCMS: retention time 7.33 min, M⁺ 163, 92% (method A).

Intermediate 14 1-(4-Bromo-3-fluorophenyl)ethan-1-one

To a stirred solution of 4-bromo-3-fluoro-N-methoxy-N-methylbenzamide(Intermediate 15, 1.17 kg, 4.46 mol) in THF (11.7 L), was added MeMgCl(3 M solution in THF; 2.53 L, 7.59 mol) dropwise at 0° C. The reactionwas stirred at room temperature for 2 h. The reaction mixture wasquenched by dropwise addition of saturated ammonium chloride solution(200 mL). The resulting solution was diluted with water (6 L) andextracted with ethyl acetate (2×5 L). The combined organic layers weredried over sodium sulphate and concentrated under reduced pressure. Theresidue was purified by silica gel column chromatography (silica 100-200mesh), eluting with 8% ethyl acetate in petroleum ether to afford thetitle compound (890 g, 91.8%) as a pale yellow solid. ¹HNMR (400 MHz,CDCl₃): δ ppm 7.72-7.65 (m, 2H), 7.63-7.59 (m, 1H), 2.59 (s, 3H). GCMS:retention time 7.38 min. M⁺ 216, 96% (method A).

Intermediate 15 4-Bromo-3-fluoro-N-methoxy-N-methylbenzamide

To a stirred solution of 4-bromo-3-fluorobenzoic acid (1.0 kg, 4.566mol) in dichloromethane (5 L), was added oxalyl chloride (587.2 mL,6.849 mol) at 0° C., followed by dropwise addition of dry DMF (20 mL,0.02 vol) at 0° C. Reaction was stirred at room temperature for 3 h. Thereaction solvent was evaporated under reduced pressure and argonatmosphere to afford a yellow liquid (1.08 Kg), which was directly takenfor next reaction. To a stirred solution of NO-dimethylhydroxylaminehydrochloride (0.532 kg, 5.46 mol) in dichloromethane (10 L) was addedtriethylamine (2.53 L, 18.19 mol) at 0° C. and the reaction stirred for15 min. To this mixture, a solution of above prepared liquid (1.08 Kg)in dichloromethane (1 L) was added dropwise. The reaction was stirred atroom temperature for 2 h. The reaction mixture was diluted with water (4L) and extracted with dichloromethane (2×4 L). The combined organicextracts were washed with IN hydrochloric acid (5 L) then saturatedNaHCO₃ solution (5 L), dried over anhydrous sodium sulphate andconcentrated under reduced pressure to afford the title compound (1.17kg, 98%) as light brown liquid which was used without furtherpurification. ¹H NMR (400 MHz, CDCl₃): δ ppm 7.61-7.59 (m, 1H),7.51-7.49 (m, 1H), 7.42-7.40 (m, 1H), 3.55 (s, 3H), 3.36 (s, 3H); LCMS(ESI): retention time 3.29 min, MH⁺ 262, 93.3% (method 1).

Compound 2 (Alternative Preparation)(R)-4-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamideHydrochloride Salt

To a stirred solution of(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide(Compound 3, 1.7 g, 3.85 mmol) in methanol (5 mL), was added 3N HCl inmethanol (4 mL) at 0° C. and stirred for 20 min. The solvent wasevaporated under reduced pressure at 25° C. The residue was dissolved inmilliQ ultrapure water (5 ml) and dried by lyophilisation. Due toresidual formic acid the salt formation was repeated to give the titlecompound as an off-white solid (1.745 g, 100%). LCMS (ESI): retentiontime 1.99 min, MH+ 442; 99.5% (method A). Chiral HPLC: retention time3.67 min, e.e. 99.85% (method C).

Compound 3 (Alternative Preparation)(R)-4-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

To(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 6, 2.6 g, 5.70 mmol) was added methanolic ammonia (150 mL)at 0° C. The reaction was allowed to stir at room temperature for 24 h.The reaction solution was concentrated at 25° C. under a nitrogenatmosphere. The residue was purified by preparative HPLC (column:Atlantis T3 C18 (250×19 mm, 5μ, eluent: 0.1% formic acid in water(A)/acetonitrile (B), gradient: 0/10, 10/45, 12.2/45, 13/100, 16/100,16.5/10, 20/10, flow: 18 ml/min) to give the title compound as a whitesolid (1.7 g, 63%). LCMS (ESI): retention time 1.99 min; MH+ 442; 99.1%(method O).

Intermediate 6 (Alternative Preparation) Methyl(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidate

A stirred solution of(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 7, 2.5 g, 5.89 mmol) in methanol (1.6 L) was saturatedwith HCl gas at −10° C. The reaction was allowed to stir at roomtemperature for 24 h. The reaction solution was concentrated underreduced pressure and an argon atmosphere at 25° C. to afford the crudetitle compound (2.7 g) as a pale yellow sticky solid, which was directlytaken for next reaction.

LCMS (ESI): retention time 2.06 min; MH+ 457; 78% (method O).

Intermediate 7 (Alternative Preparation)(R)-4-(1-Hydroxy-7-(trifluoromethyl)-3,4-dihydro-H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile

To a stirred solution of4-(2-(2-bromo-4-(trifluoromethyl)phenyl)-1-hydroxyethyl)-2-(pyridin-3-ylmethoxy)benzonitrile(Intermediate 2, 5 g, 10.47 mmol) in 1,4-dioxane (150 mL), tert-butyldiphenylphosphine (253 mg, 1.04 mmol) was added and the mixturedegassed. Pd(OAc)₂ (352 mg, 0.52 mmol) was added and the mixturedegassed. Bis(neopentyl glycolato)diboron (11.78 g, 52.38 mmol) wasadded and the mixture degassed. Finally potassium acetate (4.11 g, 41.9mmol) was added and the mixture degassed. The reaction was stirred at75° C. in a sealed tube for 2 h. The reaction mixture was filteredthrough a CELITE pad, treated with charcoal and filtered through CELITE.The filtrate was washed with water (5×2 L), brine (2×50 mL) dried overNa₂SO₄ and concentrated to afford the racemic compound (5.2 g) as anoff-white solid.

This material was combined with a further 8.0 g of crude racemiccompound which had been similarly prepared. The combined sample waswashed with ether, isolated by filtration and dried (6.13 g).

The 2 enantiomers were separated by chiral SFC (column: CHIRALCEL OD-H280×4.6 mm, 5μ, solvent CO₂ 75%, 30 mm methanolic ammonia 25%, flow: 3.0g/min, back pressure: 100 bar, temperature: 30° C., uv detection 210nm). The samples were isolated by distillation under vacuum at 20° C.

Peak 1:(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile,off white solid (2.5 g), LCMS retention time 2.74 min; MH+ 425; 78%(method O); chiral HPLC retention time 4.27 min, 99.9% e.e (method D).Peak 2:(S)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrileoff white solid (2.5 g), LCMS retention time 2.73 min; MH+ 425; 78%(method O); chiral HPLC retention time 6.19 min, 98.9% e.e (method D).

Compounds 4 to 8 (see Table) were prepared using general reactionSchemes 1 to 12. Compounds 4 to 8 may also be prepared using procedures(or procedures similar to those) described for the preparation ofCompounds 1 to 3 from the corresponding starting materials.

For example, Compound 4 may be prepared in a similar fashion to Compound3 (Alternative Preparation) from(S)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzonitrile[see preparation of Intermediate 7 (Alternative Preparation)].

For example, Compound 5 may be prepared in a similar fashion to Compound1 by replacing 4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile with4-acetyl-2-(3-chlorobenzoxy)benzonitrile in the preparation ofIntermediate 3).

For example, Compound 6 may be prepared in a similar fashion to Compound1 by replacing 4-acetyl-2-(pyridin-3-ylmethoxy)benzonitrile with4-acetylbenzonitrile in the preparation of Intermediate 3.

For example, Compound 7 may be prepared in a similar fashion to Compound1 by replacing 2-bromo-1-iodo-4-(trifluromethyl)benzene with2-bromo-5-chloro-4-fluoro-1-iodobenzene in the preparation ofIntermediate 3.

For example, Compound 8 may be prepared in a similar fashion to Compound1 by replacing 2-bromo-1-iodo-4-(trifluoromethyl)benzene with2-bromo-1-iodobenzene in the preparation of Intermediate 3.

Any necessary variations in the reaction conditions, reaction time andwork-up procedure will be familiar to the skilled chemist. The compoundsin the Table were isolated as racemic mixtures of enantiomers exceptwhere indicated.

TABLE Retention Compound Mass/ time LCMS Number Structure Mass ion (min)method 4

442/ MH⁺ 1.62 A S enantiomer 5

475/ MH⁺ 3.02 2 6

335/ MH⁺ 1.71 1 7

425/ MH⁺ 4.10 D 8

374/ MH⁺ 1.22 1

Biological Assays

Preparation of KLK5 Protein

Recombinant KLK5 protein was generated from a recombinant baculovirususing the BAC-TO-BAC system (INVITROGEN) (pFastBac_hKLK5_6His-Q-FLAG)expressed in 5 L of Spodoptera frugiperda Super 9 insect cells with aviral infection rate of 1.0. The protein was secreted into HYCLONE SFXgrowth media (GE HEALTHCARE) from which it was extracted on a 5 mLHISTRAP EXCEL column (GE HEALTHCARE). The column was washed with 500 mMNaCl, 20 mM Tris pH 7.4 buffer and the protein eluted using 500 mMimidazole in 250 mM NaCl, 20 mM Tris pH 7.4 buffer. The eluent wascaptured on a 5 mL, ANTI-FLAG M2 Affinity Gel column (SIGMA). KLK5 waseluted by competing off the bound protein with 0.2 mg/mL FLAG peptide(SIGMA) in 50 mM NaCl, 20 mM Tris-HCl pH 7.4 buffer. 1 M CaCl₂ was addedto the pooled fractions to a final concentration 2 mM and these weretreated with 0.1 U of enterokinase (NOVAGEN) per μg of target protein.The proteins were incubated at room temperature for ˜48 h. The cleavedprotein was then further purified on a 1 mL Heparin HP HITRAP column (GEHEALTHCARE) in 20 mM MOPS, pH 6.8 buffer, washed with 100 mM NaCl in2 0mM MOPS, pH 6.8 buffer and eluted with 700 mM NaCl in this buffer.Fractions containing KLK5 were pooled and concentrated using an AMICONconcentrator with a molecular weight cut off of 10000 Da. Forcryoprotection, glycerol was added to a final concentration of 50%. Allpurifications were carried out using a semi-automated ÄKTA systems fromGE HEALTHCARE.

Kinetic FLINT KLK5 Assay

11 point, 3-fold serial dilutions of each supporting compound wereprepared in DMSO and 50 nL of these solutions were dispensed into blackLV 384-well plates (GREINER BIO-ONE, Stonehouse, UK) using an ECHO 555acoustic dispenser (LABCYTE, Sunnyvale, Calif.). This gave a final assayconcentration range between 10 μM and 0.5 nM in 5 μL final assay volume.50 nL DMSO was dispensed into columns 6 and 18 for high and lowcontrols, respectively. The assay plates were sealed and stored at 4° C.until required.

Conditions for the assay of human kallikrein 5 recombinant enzyme(KLK5), were 100 mM sodium phosphate, pH 8, 1 mM CHAPS, 7.5 nM KLK5enzyme (see above for preparation), 9 uM peptide substrate((Tos-Gly-Pro-Arg)₂[R110]0.2TFA) in a total reaction volume of 5 μL.

Assays were performed by initially dispensing 2.5 μL of an enzymesolution (15 nM KLK5 in sodium phosphate. pH 8, 1 mM CHAPS) into allwells of the assay plate (except for column 18) then, 2.5 μL of bufferto column 18 (to generate low controls). Reactions were initiated byaddition of 2.5 μL of substrate solution [18 uM(Tos-Gly-Pro-Arg)₂[R110]0.2TFA (Cambridge Research Biochemicals) insodium phosphate, pH 8, 1 mM CHAPS] to all wells. Plates wereimmediately centrifuged to reach 1000 rpm before transfer to the reader.All additions were made using a MULTIDROP COMBI dispenser (THERMO FISHERSCIENTIFIC). The assay plates were transferred to a PERKIN ELMERVIEWLUX. The plates were excited at 485 nm and the rates of Rhodamine110 fluorescent emission measured at 535 nm, following cleavage of thesubstrate by KLK5. Ten measurements were taken over 5 minutes with aread interval of 30 seconds.

Data Analysis

Data analysis was performed within ACTIVITY BASE (ID BUSINESS SOLUTIONSLTD, Surrey, UK).

From the raw data, the enzyme reaction rates were calculated as relativefluorescence units (RFU). Using the 10 reads collected, per well, astraight line was fitted through data. Initial rates were calculatedfrom the slope of the reaction progress curves. The rate data wasnormalised to % inhibition between high controls in column 6 (0%inhibition) and low controls in column 18 (100% inhibition). Doseresponse curves were fitted using the IDBS Primary module fit. The datawere fitted by means of a four-parameter fit logistic:

$y = {\frac{A - D}{\left( {1 + \left( {x/C} \right)^{B}} \right)} + D}$Where x is the inhibitor concentration, y is inhibition (%), A is theminimum response, D is the maximum response. C is the IC50 for the curveand B is the Hill slope. The −log(IC50) gives the pIC50.

All Supporting Compounds were tested in the above assay. Each compoundwas tested more than once. The average pIC50 for each compound is asfollows: Compound 1 gave a pIC50 of 8.5.

Compound 2 gave a pIC50 of 8.4.

Compound 3 gave a pIC50 of 7.4.

Compound 4 gave a pIC50 of 8.4.

Compound 5 gave a pIC50 of 8.1.

Compound 6 gave a pIC50 of 8.0.

Compound 7 gave a pIC50 of 8.1.

Compound 8 gave a pIC50 of 8.2.

The invention claimed is:
 1. A method of treating a disease or conditionmediated by a kallikrein 5 (KLK-5) receptor in a patient comprising atleast a step of administering to said patient an effective amount of acompound of formula (I):

or a pharmaceutically acceptable salt thereof, wherein R¹ is H, R² isCF₃ and R³ is 3-pyridylmethoxy, 3-chlorobenzyloxy or H; R¹ is Cl, R² isF and R³ is 3-pyridylmethoxy; or R¹ is H, R² is H and R³ is3-pyridylmethoxy, wherein the disease or condition is selected from thegroup consisting of: Netherton syndrome, rosacea, atopic dermatitis,psoriasis and itch.
 2. The method according to claim 1 wherein thecompound of formula (I) is selected from the group consisting of:4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide;2-((3-chlorobenzyl)oxy)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide;4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide;4-(6-chloro-7-fluoro-1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide;and4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide.3. The method according to claim 1 wherein the compound of formula (I)is4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.
 4. The method accordingto claim 1 wherein the compound of formula (I) is2-((3-chlorobenzyl)oxy)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide

or a pharmaceutically acceptable salt thereof.
 5. The method accordingto claim 1 wherein the compound of formula (I) is4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide

or a pharmaceutically acceptable salt thereof.
 6. The method accordingto claim 1 wherein the compound of formula (I) is4-(6-chloro-7-fluoro-1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.
 7. The method accordingto claim 1 wherein the compound of formula (I) is4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.
 8. The method accordingto claim 1 wherein the compound of formula (I) is(R)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.
 9. The method accordingto claim 1 wherein the compound of formula (I) is(S)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide

or a pharmaceutically acceptable salt thereof.
 10. The method accordingto claim 1 wherein the compound of formula (I) or a pharmaceuticallyacceptable salt thereof is contained in a pharmaceutical compositionwith one or more pharmaceutically acceptable excipients.
 11. The methodaccording to claim 10 wherein the pharmaceutical composition isformulated in a dosage form adapted for topical administration.
 12. Themethod according to claim 11 wherein the pharmaceutical composition isformulated in a dosage form adapted for topical administration selectedfrom creams, ointments, lotions, solutions, pastes, sprays, foams andgels.
 13. The method according to claim 10 wherein the pharmaceuticalcomposition comprises from 0.001% to 10% w/w of the compound of formula(I) or a pharmaceutically acceptable salt thereof.
 14. A method forpreparing a pharmaceutical composition comprising at least a step ofmixing a compound of formula (I):

or a pharmaceutically salt thereof, wherein R¹ is H, R² is CF₃ and R³ is3-pyridylmethoxy, 3-chlorobenzyloxy or H; R¹ is Cl, R² is F and R³ is3-pyridylmethoxy; or R¹ is H, R² is H and R³ is 3-pyridylmethoxy, withone or more pharmaceutically acceptable excipients.
 15. The method ofclaim 14 comprising at least the step of mixing: 0.05 to 3000 mg of acompound of formula (I) or a pharmaceutically acceptable salt thereof,with 0.1 to 100 g of one or more pharmaceutically acceptable excipients.16. The method of claim 14, wherein the compound of formula (I) isselected from the group consisting of:4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide;2-((3-chlorobenzyl)oxy)-4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide;4-(1-hydroxy-7-(trifluoromethyl)-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)benzimidamide;4-(6-chloro-7-fluoro-1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide;and4-(1-hydroxy-3,4-dihydro-1H-benzo[c][1,2]oxaborinin-3-yl)-2-(pyridin-3-ylmethoxy)benzimidamide.17. The method of claim 14, wherein the one or more pharmaceuticallyacceptable excipients are selected from the group consisting ofdiluents, fillers, binders, disintegrants, lubricants, glidants,granulating agents, coating agents, wetting agents, solvents,co-solvents, suspending agents, emulsifiers, sweeteners, flavouringagents, flavour masking agents, colouring agents, anticaking agents,humectants, chelating agents, plasticizers, viscosity increasing agents,rate modifying agents, antioxidants, preservatives, stabilizers,surfactants, and buffering agents.
 18. The method of claim 14 furthercomprising the step of formulating the pharmaceutical composition into adosage form adapted for oral administration; parenteral; transdermaladministration; rectal and vaginal administration; inhalation andintranasal; topical administration; or buccal and sublingualadministration.
 19. The method of claim 18, wherein the dosage form isadapted for topical administration.